The rail industry, for both passenger and freight trains, is an important industry worldwide. Obviously the safety and reliability of train systems is crucial. Rail systems are particularly vulnerable to catastrophic accidents since trains travel on fixed tracks at speeds that prevent them from being able to stop quickly.
Railway signaling systems are used to communicate a multitude of information to various railway personnel. Various types of trackside equipment (point/switch machine, signals, track circuits) are used along the track line. Trackside equipment can communicate different types of information, such as track status, required speeds, etc., all being crucial to preventing trains from colliding.
The consequence of failure of trackside equipment can be disastrous. As such, current systems employ safety methods to mitigate failure or error. Regular maintenance of trackside equipment must also be taken into account.
Generally, trackside equipment is managed by devices such as interlockings and zone controllers. Typically these controllers manage trackside field equipment through vital relay groups. In some cases, custom direct drive boards have been developed to interface with particular equipment types.
Existing known solutions which manage dual outputs (redundant configuration for zone controllers) are controlled through an external hardware “OR” device, which is a single point of failure. Additionally, these design solutions are configured only as active-passive and thus manage a controlled switchover which interrupts the final condition.